1. Field of the Invention
This invention relates to a drive chain belt for V-pulley type stepless transmissions.
2. Description of the Prior Art
The drive belts which are used for stepless transmissions can be classified into a rubber type and a metal type, of which the metal type drive belts are preferred in those cases where heat resistance and durability are important factors.
The metal type drive belt consists of a flexible endless chain formed by a plural number of rows of link members in the form of metal plates which are pivotally connected end to end by a pin inserted at each pitch. The drive chain is passed around V-type pulleys on a drive shaft and a driven shaft of a transmission, between opposing inclined inner walls which are movable toward and away from each other to vary steplessly the speed of power to be transmitted from the drive shaft to the driven shaft. In this connection, the transmission of power from the drive shaft to the driven shaft has thus far been effected by the frictional force which is produced by abutting engagement of the opposite end portions of the pins with the inclined inner walls of the pulleys. However, the above-mentioned arrangement involves problems in that the contact area of the link plate connecting pins with the V-type pulleys is insufficient to ensure satisfactory power transmission efficiency, and in that the power transmitting operation is instabilized by variations in contact area of the pins relative to the pulleys, which are caused depending upon the contacting positions of the pins with a circular shape in section. In addition, there has been a problem of vibrations resulting from the clenching action of the pulleys on the chain belt.